| Abstract
| - Fluorescence microscopy, in combination with atomic force microscopy (AFM), reveals that rhodamine-labeled lysozyme adsorbs strongly from aqueous solution to polishing marks of nanometer depths on fusedsilica surfaces. The fluorescence and topographical images correspond closely. Fluorescence intensity variesby as much as 2-fold over the same region where the topography varies over 2.5 nm. Desorption of lysozymefrom the surface occurs on rinsing with solutions of increased ionic strength or decreased pH, showing thatreducing the Coulombic attraction enhances desorption. Different polishing marks behave differently withrespect to desorption: the fluorescence pattern on the surface changes when the ionic strength of therinsing solution reaches 0.1 M, indicating that some polishing marks are more strongly adsorptive thanare others. The desorption depends on pH, which is consistent with the known variation in the charge ofsilica surface. A superpolished silica photomask, which has significantly fewer polishing marks on thenanometer scale, has significantly less adsorption of lysozyme, suggesting that the topography on thenanometer scale influences adsorption.
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